| Parameter |
Value |
| Designation |
C/2003 H1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2004-02-22T14:57:51.929280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:29Z |
| Obs used |
1890 |
| NEO |
- |
| M1 |
11.000 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2003-08-30.0000000 |
| e |
0.99915679 |
| q (au) |
2.239626 |
| a (au) |
2656.070310 |
| i (deg) |
138.667213 |
| Ω (om, deg) |
19.000486 |
| ω (w, deg) |
196.139594 |
| M (ma, deg) |
359.998728 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.871 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.871 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.730 |
| k |
0.800 |
| δ90 |
10.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2003-04-24 |
2004-02-21 |
+3.5205 |
-2.057 |
| 2004-02-23 |
2005-02-07 |
+17.2256 |
-6.015 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
01:54:28.13 |
+04:28:50.2 |
HIP 8765 |
27.34 |
| 2026-07-29 12:00 |
01:54:27.74 |
+04:28:44.4 |
HIP 8765 |
27.29 |
| 2026-07-30 00:00 |
01:54:27.33 |
+04:28:38.4 |
HIP 8765 |
27.24 |
| 2026-07-30 12:00 |
01:54:26.90 |
+04:28:32.2 |
HIP 8765 |
27.19 |
| 2026-07-31 00:00 |
01:54:26.44 |
+04:28:26.0 |
HIP 8765 |
27.13 |
| 2026-07-31 12:00 |
01:54:25.97 |
+04:28:19.7 |
HIP 8765 |
27.06 |
| 2026-08-01 00:00 |
01:54:25.47 |
+04:28:13.2 |
HIP 8765 |
27.00 |
| 2026-08-01 12:00 |
01:54:24.95 |
+04:28:06.6 |
HIP 8765 |
26.93 |
| 2026-08-02 00:00 |
01:54:24.41 |
+04:28:00.0 |
HIP 8765 |
26.86 |
| 2026-08-02 12:00 |
01:54:23.85 |
+04:27:53.1 |
HIP 8765 |
26.78 |
| 2026-08-03 00:00 |
01:54:23.26 |
+04:27:46.2 |
HIP 8765 |
26.70 |
| 2026-08-03 12:00 |
01:54:22.66 |
+04:27:39.1 |
HIP 8765 |
26.62 |
| 2026-08-04 00:00 |
01:54:22.03 |
+04:27:32.0 |
HIP 8765 |
26.54 |
| 2026-08-04 12:00 |
01:54:21.38 |
+04:27:24.7 |
HIP 8765 |
26.45 |
| 2026-08-05 00:00 |
01:54:20.71 |
+04:27:17.3 |
HIP 8765 |
26.36 |
| 2026-08-05 12:00 |
01:54:20.02 |
+04:27:09.8 |
HIP 8765 |
26.27 |
| 2026-08-06 00:00 |
01:54:19.30 |
+04:27:02.2 |
HIP 8765 |
26.17 |
| 2026-08-06 12:00 |
01:54:18.57 |
+04:26:54.5 |
HIP 8765 |
26.08 |
| 2026-08-07 00:00 |
01:54:17.81 |
+04:26:46.7 |
HIP 8765 |
25.98 |
| 2026-08-07 12:00 |
01:54:17.03 |
+04:26:38.8 |
HIP 8765 |
25.88 |
| 2026-08-08 00:00 |
01:54:16.23 |
+04:26:30.7 |
HIP 8765 |
25.77 |
| 2026-08-08 12:00 |
01:54:15.40 |
+04:26:22.5 |
HIP 8765 |
25.67 |
| 2026-08-09 00:00 |
01:54:14.56 |
+04:26:14.3 |
HIP 8765 |
25.56 |
| 2026-08-09 12:00 |
01:54:13.69 |
+04:26:05.9 |
HIP 8765 |
25.45 |
| 2026-08-10 00:00 |
01:54:12.81 |
+04:25:57.4 |
HIP 8765 |
25.34 |
| 2026-08-10 12:00 |
01:54:11.90 |
+04:25:48.8 |
HIP 8765 |
25.23 |
| 2026-08-11 00:00 |
01:54:10.97 |
+04:25:40.1 |
HIP 8765 |
25.12 |
| 2026-08-11 12:00 |
01:54:10.01 |
+04:25:31.3 |
HIP 8765 |
25.01 |
| 2026-08-12 00:00 |
01:54:09.04 |
+04:25:22.4 |
HIP 8765 |
24.90 |
| 2026-08-12 12:00 |
01:54:08.04 |
+04:25:13.4 |
HIP 8765 |
24.78 |
| 2026-08-13 00:00 |
01:54:07.03 |
+04:25:04.2 |
HIP 8765 |
24.67 |
| 2026-08-13 12:00 |
01:54:05.99 |
+04:24:55.0 |
HIP 8765 |
24.55 |
| 2026-08-14 00:00 |
01:54:04.93 |
+04:24:45.7 |
HIP 8765 |
24.44 |
| 2026-08-14 12:00 |
01:54:03.85 |
+04:24:36.2 |
HIP 8765 |
24.33 |
| 2026-08-15 00:00 |
01:54:02.75 |
+04:24:26.7 |
HIP 8765 |
24.21 |
| 2026-08-15 12:00 |
01:54:01.63 |
+04:24:17.1 |
HIP 8765 |
24.10 |
| 2026-08-16 00:00 |
01:54:00.49 |
+04:24:07.3 |
HIP 8765 |
23.99 |
| 2026-08-16 12:00 |
01:53:59.32 |
+04:23:57.5 |
HIP 8765 |
23.88 |
| 2026-08-17 00:00 |
01:53:58.14 |
+04:23:47.5 |
HIP 8765 |
23.77 |
| 2026-08-17 12:00 |
01:53:56.93 |
+04:23:37.5 |
HIP 8765 |
23.66 |
| 2026-08-18 00:00 |
01:53:55.71 |
+04:23:27.4 |
HIP 8765 |
23.56 |
| 2026-08-18 12:00 |
01:53:54.46 |
+04:23:17.2 |
HIP 8765 |
23.45 |
| 2026-08-19 00:00 |
01:53:53.20 |
+04:23:06.8 |
HIP 8765 |
23.35 |